Stanley's healthcare division has scooped up Wi-Fi tracking leader AeroScout, with a view to pushing the technology into hospitals – for use where RFID isn't good enough.

Stanley Healthcare will spend the next year adding AeroScout's Wi-Fi based real-time location system to its product portfolio, as well as integrating the systems with its own management software, to provide tracking of both people and kit around the hospitals and care homes which make up the company's 15,000-strong customer base.

AeroScout started out in 1999, and initially used Bluetooth to track locations, but changed its identity to align with its now-eponymous AeroScout product, which uses existing Wi-Fi infrastructure to track tags small enough to be strapped to a trolley or worn on a belt. RFID Journal tells us the acquisition won't see changes in the AeroScout management, or offices, as the companies' offerings are complementary.

Stanley, a company that will always be known as the knife people, merged with Black & Decker (the drill people) back in 2009, but it is its healthcare division which is interested in AeroScout. The firm is hoping to use the tech to monitor movements of patents and kit around hospitals though the magic of Wi-Fi fingerprinting.

The technique isn't complicated to understand, though it may well be difficult to implement: one just maps the coverage of existing Wi-Fi networks, measuring and plotting the relative strengths at different points in the hospital. Tags attached to hospital kit (and/or people) record the networks available at their location and a server deduces the latter from the former.

The joy is the use of existing infrastructure and the range: the system works anywhere more than one Wi-Fi network is available. The drawback is that humans absorb Wi-Fi, so if people are going to be wandering around the place (as they might in a hospital) then the accuracy is limited to around five metres, though AeroScout's tags have an ultrasound backup to improve on that.

But five meters is good enough for most applications, and certainly superior to the RFID systems deployed by many of Stanley Healthcare's 15,000 deployments (4,800 hospitals, 11,000 "long-term care organisations"). Short range RFID tags can use local readers, blanketing an area such as a maternity ward for the "Hugs & Kisses Infant protection" system, or covering exits as used on the basic "Wander Management" range for the bewildered, but covering an entire hospital is a lot easier with Wi-Fi.

Real time location systems are proliferating at the moment, with various technologies and techniques vying to provide the equivalent of GPS indoors. Strangely Nokia has been particularly innovative in this regard, demonstrating highly directional Bluetooth 4 antennas which offer centimetre accuracy, and an unrelated system using the to-be-built White Space location database (into which every White Space transmitter is recorded) to work out its own location to an accuracy of two metres without any new infrastructure at all, but the engineers working on both projects face an uncertain future.

With so many locations already blanketed in Wi-Fi, the approach taken by AeroScout (and market leaders Ekahau) could well come to dominate the indoor RTLS industry, making Stanley Heathcare's acquisition of AeroScout.a wise move indeed. ®